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A very uniform, dimensionally stable, urethane-based series of tooling boards has been developed for use in prototype, composite tooling, foundry pattern, fixture and other applications and features fast, easy machining, excellent uniformity, superior edge definition, better chip formation, very fine surface structure, and ease of sanding.

Features

According to Curbell Plastics Business Development Manager Rick Delaney, the tooling boards are suitable for a wide range of applications. “These boards are replacing mahogany, jelutong and pine because of their outstanding dimensional stability and lack of grain," he says.

These new grades were developed in response to moldmakers’/modelmakers’ requests for materials that allowed for fast feedrates in their CNC equipment and required minimal sanding afterwards. Also, the boards’ uniformity is especially appreciated by users who have been disappointed in the past by inferior urethane boards, which suffered from “voids” or bubbles, Delaney notes. “When machining opens up a void, this must be filled with repair paste, allowed to cure and then sanded,” he says. “This all takes time and can be a real problem when deadlines are tight.”

Applications

Rapid Prototyping/Rapid Manufacturing “A CNC machining center is used to convert a CAD file to a 3D model using medium density urethane modeling board,” Delaney explains. “An RTV silicone mold can then be made from the modeling board model. At that point a urethane or epoxy casting resin can be used to create numerous replicas from the RTV silicone mold. This method is often used when required quantities are small—perhaps 100 or fewer.”

Composite Tooling“As fiber-reinforced composites have grown in usage, so has the demand for tooling,” Delaney comments. “Wood has been widely used for the largest tools, due to cost. However, wood will not keep tight tolerances due to variations in moisture content. Also, some high-density woods traditionally used for mold and modelmaking—such as mahogany—have shown significant cost increases in recent years. For these reasons, many jobs have been switched from wood to urethane tooling boards. An added benefit is improved consistency.”

Thermoforming “Thermoformers are switching from wood molds and plugs to Rampf modeling boards,” Delaney states. “Densities of 60 to 80 pounds per cubic foot are most commonly used. They are quickly and easily machined by hand or on CNC equip-ment and exhibit a fine surface with minimal sanding. Thermoforming molds require good heat resistance, edge strength and durability in order to maximize tool life. These tooling boards provide an excellent balance of performance and economy.”